Method and apparatus for aeration of liquid medium in a pipe

ABSTRACT

An apparatus and method for mixing gas and liquid comprising a pipe having an enclosure positioned in-line with said pipe, wherein a sealed space is defined, at least one blower, said blower regulates the barometric pressure in said sealed space, wherein intermeshed rotating sets of discs operate on parallel shafts driven by variable speed drives, and strakes are radially mounted on the discs to carry liquid up into a mixing area and to carry air and liquid down into a mixing area resulting in a shear force that drives air into the oxygen depleted liquid. In the sealed space the barometric pressure is raised by a blower, in order to pop foam bubbles and allow for optimum mixing of air into the oxygen depleted liquid and to regulate the waterline within the sealed space, thereby preventing the escape of foam, noise and odorous gases into the local environment.

CROSS-REFERENCE AND PRIORITY CLAIM TO RELATED APPLICATIONS

To the fullest extent permitted by law, the present Continuation-in-partpatent application cross-references and claims priority to and the fullbenefit of divisional non-provisional patent application entitled“METHOD AND APPARATUS FOR AERATION OF LIQUID MEDIUM”, filed on Aug. 7,2008, having assigned Ser. No. 12/187,905 and having issued on May 12,2009 under U.S. Pat. No. 7,531,097, incorporated herein by reference inits entirety, which claims priority to and the full benefit ofnon-provisional patent application entitled “METHOD AND APPARATUS FORAERATION OF LIQUID MEDIUM”, filed on May 17, 2005, having assigned Ser.No. 11/131,113 and having issued on Sep. 23, 2008 under U.S. Pat. No.7,427,058, incorporated herein by reference in its entirety.

TECHNICAL FIELD

This invention relates to an apparatus and method for mixing gas, suchas air, with liquid, and more particularly the invention relates toaeration of wastewater, sewage and industrial waste including any bodyof water or liquid.

BACKGROUND OF THE INVENTION

Wastewater from both municipal sewage systems and from industrial wasteproduct exhausting systems is usually collected in large ponds, ditches,or basins that are referred to as wastewater ponds. Such ponds may be afew to several feet deep and may cover quite a number of acres ofsurface area. The wastewater usually includes large amounts of organicand inorganic waste material that, if left untreated, creates severeodors and can generates toxic products.

Moreover, EPA has published dissolved oxygen (DO) criteria for freshwater, saltwater, and discharges into the same bodies of water toprotect organisms and their uses from the adverse effects of low DOconditions. The Agency developed these criteria because hypoxia (lowdissolved oxygen) is a significant problem for lakes, streams, rivers,and coastal waters that receive a lot of runoff that contain nutrients(for example, nitrogen and phosphorous and other oxygen-demandingbiological wastes). Excessive nutrients in aquatic systems stimulatealgal growth, which in turn uses up the oxygen needed to maintainhealthy fish, shellfish, and other aquatic life populations.

EPA's Environmental Monitoring and Assessment Program (EMAP) for lakes,streams, rivers, and coastal waters has shown areas exposed to somedissolved oxygen concentrations of less than 5 mg/L. Long periods of DObelow 5 mg/L can harm larval life stages for many fish, shellfish, andother aquatic life populations.

The EPA's dissolved oxygen criteria apply to both continuous and cycliclow DO conditions. If the DO conditions are always above the chroniccriterion for growth (4.8 mg/L), the aquatic life at that locationshould not be harmed. If the DO conditions at a site are below thejuvenile/adult survival criterion (2.3 mg/L), there is not enough DO toprotect aquatic life.

Under the Clean Water Act (CWA), states, territories, and tribes mustadopt water quality criteria to protect designated uses. The EPA haspromulgated regulations to implement this requirement including levelsof DO (see 40 CFR 131).

The most common method of wastewater treatment uses an activated sludgeprocess. This process involves three major steps. The primary treatmentstage consists of a simple separation between dense sludge, which issent to an incinerator or land fill, and the remaining effluent liquidsludge which then undergoes secondary treatment. Secondary treatment iswhere the biochemical consumption of organic material takes place. Themicroorganisms present in the liquid sludge feast on the biomass in thewastewater pond. Extensive aeration is needed for the bacteria toconsume the organic wastes.

The third phase of treatment can be simple or extensive depending uponthe extent of pollution and the requirements for water purity. Itspurpose is to remove inorganic pollutants as well as any organic massnot removed by the primary and secondary stages. Lastly, the treatedwater is discharged back into the environment. This discharge must meetfederal, state, county and city government standards for dischargedwater, such as minimum dissolved oxygen levels deemed necessary toaccommodate marine life, before such wastewater can be discharged into ariver or stream.

The activated sludge process is a biochemical process in which aerobicbacteria consume the organic pollutants in wastewater. Because thebacteria are aerobic, their efficiency of consumption is very dependentupon the amount of available oxygen dissolved in the liquid sludge. Inthe wastewater treatment process, aeration introduces air into a liquid,providing an aerobic environment for microbial degradation of organicmatter. The purpose of aeration is two-fold: to supply the requiredoxygen to the metabolizing microorganisms and to provide mixing so thatthe microorganisms come into intimate contact with the dissolved andsuspended organic matter.

Various aeration approaches have been used; the two most common aerationsystems are subsurface and mechanical. In subsurface aeration systems,air or oxygen is pumped below the surface to a diffuser or other devicesubmerged in the wastewater. Fine pore diffusion is a subsurface form ofaeration in which air is introduced in the form of very small bubblesinto the wastewater pond. One type of an oxygen diffuser for wastewatertreatment process requires constant movement of the diffuser todifferent levels and positions within the wastewater pond and performsminimal mixing of the wastewater and microorganisms. In addition,un-reacted air or oxygen bubbles remaining that make their way to thesurface. If oxygen is the source, then the oxygen that makes it to thesurface of the wastewater pond is wasted as it vents to the air abovethe pond.

Mechanical aeration and mixing systems take on various forms, such asdowndraft pumps, which force surface water to the bottom, updraft pumps,which produce a small fountain, and paddle wheels, which increase thesurface area of the water. In addition, all such devices mix wastewaterby moving large amounts of heavy water or hurling it into the airresulting in high energy consumption for these devices. Some suchdevices generate large amounts of odor and foam while agitating thewastewater and consume large amounts of electrical power resulting inhigh electricity cost for operation.

Therefore, it is readily apparent that there is a need for an economicalapparatus and method for aeration of wastewater, sewage and industrialwaste, and more particularly, a process for efficiently adding dissolvedoxygen into wastewater, sewage and industrial waste while minimizingodor, foam and energy consumption.

BRIEF SUMMARY OF THE INVENTION

Briefly described, in the preferred embodiment, the present inventionovercomes the above-mentioned disadvantages and meets the recognizedneed for such a device by providing a method and apparatus for mixinggas, such as air, with liquid, such as wastewater, sewage and industrialwaste in a wastewater pond.

According to its major aspects and broadly stated, the present inventionin its preferred form is a floating pressurized dome aerator device andprocess for adding dissolved oxygen into wastewater, sewage andindustrial waste.

More specifically, the preferred aerator device present invention hastwo or more partially submerged interleaved sets of discs operating inrotational unison along parallel shafts driven by variable speed drives.One or more strakes with end caps are mounted on the discs in radialfashion, extending from the hub to the edge of the disc. The strakes onone disc bring the liquid up to the wastewater line and the strakes onthe other disc bring the air down to the wastewater line and in closecontact with each other in a mixing area just below the wastewater line.This force mixes the oxygen from the air into the oxygen-depleted water,thus increasing the dissolved oxygen content of the wastewater.

Still more specifically, an apparatus and method for mixing gas andliquid comprising a pipe having an enclosure positioned in-line withsaid pipe, wherein a sealed space is defined, at least one blower, saidblower regulates the barometric pressure in said sealed space, whereinintermeshed rotating sets of discs operate on parallel shafts driven byvariable speed drives, and strakes are radially mounted on the discs tocarry liquid up into a mixing area and to carry air and liquid down intoa mixing area resulting in a shear force that drives air into the oxygendepleted liquid. In the sealed space the barometric pressure is raisedby a blower, in order to pop foam bubbles and allow for optimum mixingof air into the oxygen depleted liquid and to regulate the waterlinewithin the sealed space, thereby preventing the escape of foam, noiseand odorous gases into the local environment

Accordingly, a feature and advantage of the present invention is itsability to create a shear force between the liquid on the leading edgeof opposing strakes within the mixing area to efficiently mix the airand wastewater.

In addition, the strakes have bleed holes on their trailing face. Theend caps force wastewater fluid eddy on the liquid side and flurries ofbubbles of air on the gas side through the bleed holes of the trailingedge of the strake into the mixing area to efficiently mix the air andwastewater.

Accordingly, a feature and advantage of the present invention is itsability to sustain a larger number of aerobic dependent bacteria thantraditional methods resulting in an increased biochemical consumption oforganic material in the wastewater pond.

In use, the aerator device is placed on a floating platform to keep theaerator device at a set position relative to the water line. Thefloating apparatus is covered with an airtight cover or dome, whereinthe barometric pressure is raised under the cover or dome by an airblower to create an atmosphere under the dome with an increasedbarometric pressure.

Another feature and advantage of the present invention is that thevariable barometric pressure allows for optimum atmospheric dissolutionunder the cover or dome.

Another feature and advantage of the present invention is that the foammust travel back beneath the water line of the liquid to escape thefloating apparatus resulting in further aeration of the liquid sludge.

Another feature and advantage of the present invention is that theliquid inlet is beneath the waterline creating a sealed environment.

Another feature and advantage of the present invention is that theliquid discharge is beneath the waterline creating a sealed environment.

Another feature and advantage of the present invention is its ability tominimize foam generated during use, wherein the raised barometricpressure in the dome serves the function of popping the bubbles createdby the mechanical mixer.

Another feature and advantage of the present invention is that the coveror dome traps odorous gases preventing their escape into the localenvironment, resulting in an odor free operation.

Another feature and advantage of the present invention is that the coveror dome traps the noises generated by the mechanical agitationpreventing their escape into the local environment and resulting in anessentially noise free operation.

These and other features and advantages of the invention will becomemore apparent to one skilled in the art from the following descriptionand claims when read in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood by reading the DetailedDescription of the Preferred and Alternate Embodiments with reference tothe accompanying drawing figures, in which like reference numeralsdenote similar structure and refer to like elements throughout, and inwhich:

FIG. 1 is a cross-sectional illustration of the aeration apparatusaccording to the preferred embodiment of the present invention;

FIG. 2 is a front sectional view of the aeration apparatus of FIG. 1;

FIG. 3 is perspective view of a strake with bleed holes according to theinvention;

FIG. 4A is front sectional view of a pair of discs showing theirdirection of rotation according to the invention;

FIG. 4B is a top sectional view of disc array showing two sets of discsinterleaved amongst each other according to the invention;

FIG. 5 is an enlarged partial sectional view depicting the dynamics ofthe liquid gas mixing area, showing radial strakes and bleed holesaccording to the preferred embodiment of the present invention;

FIG. 6 is a side view of a standard industrial waste water or dischargepipe;

FIG. 7 is a side view of the pipe in FIG. 6 with a section cut out ofthe pipe and a compartmental enclosure fit between the ends of the pipe;

FIG. 8 is a side view of the pipe and enclosure in FIG. 7 with anaeration device housed in the enclosure; and

FIG. 9 is a side view of a tethered aeration apparatus of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED AND ALTERNATIVE EMBODIMENTS

In describing the preferred and alternate embodiments of the presentinvention, as illustrated in FIGS. 1-9, specific terminology is employedfor the sake of clarity. The invention, however, is not intended to belimited to the specific terminology so selected, and it is to beunderstood that each specific element includes all technical equivalentsthat operate in a similar manner to accomplish similar functions.

Referring now to FIGS. 1-9, the present invention in its preferredembodiment is a floating pressurized dome aerator device and process foradding dissolved oxygen into wastewater, sewage and or industrial waste.It is important to understand that the present invention is suitable forutilization in any liquid environment where an increase in dissolved airor gas into liquid medium is desired or beneficial; therefore, while theapparatus and method of the present invention is described convenientlywith the preferred utilization in a wastewater pond, it is not limitedto application or implementation in such wastewater pond. Furthermore,the present invention may be utilized in water such as but not limitedto a golf course pond, water with aquatic plants, as well as water withfish and/or other marine life. The apparatus and method of the presentinvention is suitable for many applications where air or other gas is tobe dissolved into a liquid medium, including but not limited to golfcourse ponds, oxygen depleted lakes, streams, and rivers as well asenvironmental and/or industrial processes.

Referring now to FIG. 1, there is illustrated a preferred fully enclosedfloating dome aerator device 10. Aerator device 10 is a mechanical gasdissolving apparatus operating in a controlled pressurized environment.Dome 12 is preferably supported by flotation device 14 proximatewaterline 24 of a pond or wastewater, sewage, industrial waste pond orother selected liquid treatment reservoir. Dome 12 includes top portion13 preferrably positioned above the surface of the pond, so as to definea space or compartmental enclosure 15 for containing mechanicalagitation of aerator device 10. Dome 12 is preferably constructed of anairtight and corrosion resistant material such as fiberglass or metal.It is recognized that other suitable materials could be utilized withoutdeparting from the intended scope of the present invention. That is,dome 12 may be constructed of any material capable of holding the areadefined by space or compartmental enclosure 15 under the dome at aselected, preferrably increased barometric pressure.

Compartmental enclosure defined by dome 12 creates a space above thewaterline 22 that can collect foam and odor generated by aerator device10. Foam generated by aerator device 10 is thus held in close proximityto aerator device 10 and must travel back beneath waterline 24 toescape, further enhancing the transfer of gas to the liquid. Odorousgases generated by the mechanical agitation of aerator device 10 arealso trapped in dome 12 preventing their escape into the surroundingenvironment resulting in an essentially odor free operation. Inaddition, dome 12 acts as a sound barrier, trapping the noises generatedby the mechanical agitation of aerator device 10, preventing theirescape into the surrounding environment, and thereby resulting in anessentially noiseless operation.

Blower 16 is preferably any common industrial variable speed rotary typeblower. Blower 16 can be of any standard design with air flow andpressure ratings capable of increasing the barometric pressure of theair under dome 12 to preferably between approximately 35-40 inches ofmercury or 1-3 psi, however, greater barometric pressure can be utilizeddepending on the gas and liquid medium being mixed. Blower 16 ispreferably rotary, but can be any fan, centrifugal, rotary or any othertype of blower or air source. Blower 16 is preferably a single unitpositioned proximate top portion 13; however, blower 16 can be in theform of a single or multiple blowers and can be located anywhere onaerator device 10 that permits air flow access to interior space 15under dome 12. In the preferred operation, blower 16 increases thebarometric pressure under dome 12 creating an ideal environment for thetransfer of gas to the liquid under dome 12, wherein coincidentallysurface area is increased via agitation and whirling of liquid byaerator device 10. In addition, the increase in barometric pressureunder dome 12 assists with popping the foam bubbles, effectivelyreducing the foam generated by aerator device 10.

Blower 16 can preferably be used for facilitating fine adjustment of theposition of the mechanical agitators of aerator device 10 relative tothe pond level 24. That is, because barometric pressure inside dome 12increases when blower 16 is in operation, this causes the liquid levelunder the dome 12 to be slightly lower than the static level of thepond.

Floatation device 14 is preferably a pontoon; however, flotation device14 can be made of any material and define any shape capable of keepingaerator device 10 afloat. Floatation device 14 is preferably attached toa submerged or floating frame 46 (not shown) for support and positioningof dome 12, lower housing 18, and other components of aerator device 10.Flotation device 14 preferably includes a ballast (not shown) to allowfor user-controlled or controller controlled height adjustment ofaerator device 10 in relation to waterline 24. Such ballast allows theoperator or controller to adjust the position of aerator device 10relative to the static pond level, the specific gravity of the liquid,or the barometric pressure under dome 12. Flotation device 14 preferablyincludes maintenance deck 26 on top side 17 of flotation device 14,wherein maintenance deck 26 preferably extends outwardly along thecircumference of dome 12.

Lower housing 18 preferably defines a partially submerged conduit havingclosed sides and bottom (not shown), thereby forming a submerged channelwith an open top (not shown) and opposing open sides 21 and 23. Lowerhousing 18 is preferably attached to frame system 46 (not shown). Lowerhousing 18 is preferably made of a watertight and corrosion resistantmaterial, however, lower housing 18 can be constructed of any materialcapable of directing the inflow and outflow of liquid through adesignated passageway. Open end 21, referenced as the intake 21,preferably has intake screen 20 to prevent debris, marine life, andlarge particulates from entering aerator device 10. In addition, openend 23 referenced as the discharge 23, preferably has discharge screen22 to prevent debris, marine life, and large particulates from enteringaerator device 10. Such screening enables positioning of intake 21 anddischarge 23 of lower housing 18 preferably submerged below the liquidline thereby creating a sealed environment and minimizing the noise,foam and odor escaping from aerator device 10.

Dome 12 is preferably affixed to lower housing 18, preferably via acorrosion resistant hinge 48 and latch 50 assembly (shown in FIG. 2).Although hinge 48 and latch 50 are preferred, any appropriate affixingmeans of any standard mechanism can be utilized, including but notlimited to nut and bolt, latch, lock, catch and/or clasp as long as theconfiguration is capable of holding dome 12 in contact with lowerhousing 18.

Drive 28 is preferably a variable speed AC or DC drive, including butnot limited to any gear reduction, belt, chain, or shaft driven. Drive28 can be any standard design with horse power, variable rotationalspeed, and directional ratings capable of rotating the mechanicalagitation of aerator device 10. Drive 28 is preferably fixed to frame 46of flotation device 14. Struts or brace members (not shown) preferablyprovide a generally rigid support for frame 46 and functions as amounting plate for drive 28. Power sources capable of operating drive 28and/or aerator device 10 include but are not limited to alternatingcurrent, direct current, compressed air and or solar power.

Controller 30 is preferably a multichanneldigital motor control.Controller 30 can be any standard drive controller that matches drive28. Controller 30 may include other features such as a blower controllerthat monitors the pressure under dome 12 and regulates blower 16 tomaintain a specified pressure under dome 12. Controller 30 may alsoinclude a scheduler to preset hourly, night and day, daily, weekly,monthly seasonal and/or other runtime schedules for aerator device 10.Controller 30 may also include inputs from environmental sensors (notshown), including but not limited to wastewater temperature, dissolvedoxygen content of the wastewater, and/or air temperature wherein eachsensor reading is preferably collected and available from inside and/oroutside aerator device 10, in addition to a light sensor to determineand record whether the measurement is collected during night or day.With these inputs, controller 30 is able to maximize the efficiency ofthe transfer rate of gas to liquid by modifying the operation of aeratordevice 10 based on essentially real-time inputs from environmentalsensors, wherein energy consumption is also minimized. Controller 30 ispreferably positioned proximate top portion 13; however, controller 30can be placed anywhere on aerator device 10 that is accessible by anoperator from maintenance deck 26 on top side 17 of flotation device 14.Controller 30 can be remotely controlled by a wireless radio frequency,infrared signal, or any other suitable transmission and receive source,thereby enabling aerator device 10 to be programmed or operated from aremote location.

As illustrated in FIG. 1, aerator device 10 preferably has lifting eye32 suitably fixed to frame 46 of flotation device 14. Lifting eye 32,together with frame 46 of flotation device 14, preferably enablesaerator device 10 to be lifted in and out of a wastewater pond via ahoist or crane. Lifting eye 32 can be in the form of a single ormultiple lifting eyes and can be located anywhere on aerator device 10suitable for attachment to frame 46 of flotation device 14.

Referring now to FIG. 2, there is illustrated a front cross-sectionalview of floating dome aerator device 10 with preferred placement of theinternal mechanics of aerator device 10 shown. Two drives 42 and 44 arepreferred and shown for aerator device 10, a leading drive 42 and atrailing drive 44. Leading drive 42 and trailing drive 44 preferablyrotationally operate in the same direction and at the same speed;however, drives 42 and 44 are preferably capable of operating atdifferent speeds. For example, trailing drive 44 could operate at 2× thespeed of leading drive 42.

Both leading drive 42 and trailing drive 44 are preferably attached toframe 46. Frame system 46 is preferably made of a light weight andcorrosion resistant material, including but not limited to tubing,cables, and/or angled iron or aluminum, or combinations of the same orany other suitable material. Frame 46 can be constructed of any materialcapable of supporting and positioning leading drive 42, trailing drive44, dome 12, lower housing 18, flotation device 14, and the other systemcomponents of aerator device 10. Lifting eye 32 is securely affixed toframe system 46.

Vane 54 is a variable flow control device that can be mounted on intake21 or discharge 23 of lower housing 18. Vane 54 is preferably made of acorrosion resistant material. A plurality of vanes 54 preferably enablecontrol of the flow of liquid into and out of lower housing 18, therebymaximizing the transfer of gas to the liquid. The positioning ofplurality of vane 54 can preferably be set by an operator or controlledby controller 30.

Referring now to FIG. 4A, a front view of a preferred disc 60 is shown.Disc 60 is preferably a thin flat disc made of corrosion resistantmaterial. Disc 60 can be constructed of any material, configurationand/or dimension capable of being rotated through the sludge ofwastewater. Possible shapes and configurations include, withoutlimitation, a star, square, hexagon, octagon, and any otherconfigurations capable of defining a mixing area and a shear force zonewithin a liquid medium. Disc 60 preferably has keyed hub 62 at itscenter for affixing disc 60 to shaft 45 (shown in FIG. 4B). Althoughkeyed hub 62 is preferred, any suitable affixing means could be utilizedof any standard design with a means to attach disc 60 to a shaft 45. Thepreferred keyed hub 62 allows for disc spacing and adjustment on shaft45, thereby maintaining proper spacing.

Referring now to FIG. 3, a perspective view of preferred strake 70 isshown. Strake 70 is preferably made of a watertight and corrosionresistant material; however, strake 70 can be constructed of anymaterial capable of carrying liquid and/or gas. Strake 70 preferably hasquarter circle, unshaped or generally triangular shaped end cap 72, openleading face 74, trailing face 75 and mounting face 76, wherein faces74, 75, 76 preferably extend lengthwise along strake 70 formingperipheral edges of a channel for strake 70 to carry liquid and/or gas.Additionally, strake 70 preferably has a plurality of bleed holes 78defined through trailing face 75.

Strake 70 can be varied in size, shape, angle, and bleed hole placementto maximize aerator device 10 dissolved gas transfer rate in any liquidmedium. For example, a smaller strake moving at a higher speed may bemore effective on wastewater with high solids content, whereas a largestrake at lower speeds may be more effective on wastewater with smallersolids and also may be less disturbing to marine life. Furthermore,strake 70 can be varied in size, shape, angle, and bleed hole placementto account for the centrifugal force on the liquid. A plurality ofstrakes 70 are preferably secured to both sides of disc 60 in a radialconfiguration with each open face 74 oriented in same direction. Eachstrake 70 is arranged in a radial configuration beginning at the centerof disc 60 and extending outward to the outer circumference edge orperipheral edge of disc 60, wherein flat face 76 of strake 70 ispreferably affixed to disc 60, preferably via corrosion resistant boltand nut (not shown). Although corrosion resistant bolt and nut arepreferred, the affixing means can of any standard mechanism, and may beselected dependent on the material used for disc 60 and strake 70,including but not limited to welding, adhesive, or epoxy. Theillustration shown in FIG. 3 is not a specification or limitation on thenumber of strakes 70 affixed to disc 60.

Referring now to FIG. 4A, a front sectional view of a pair of preferreddiscs 60 is shown, depicting the preferred arrangement, area of overlap,and direction of rotation. Leading disc 81 and trailing disc 92 arepreferably arranged so they overlap as discussed below. Both discassemblies are preferably partially submerged in a liquid medium,preferably at a depth of at least 40% of their diameter; however, bothdisc assemblies can be submerged in a liquid medium to any depth,wherein at least part of the disc assemblies are exposed to theatmosphere under dome 12. Mixing area 100 is created below liquid line24 between where the leading disc 81 and trailing disc 92 overlap asalso depicted in FIG. 5. The plurality of strakes 70 on leading disc 81capture liquid from the wastewater pond and carry it up into mixing area100. Plurality of strakes 70 on trailing disc 92 preferably capture airunderneath dome 12 and carry it down into mixing area 100.

As depicted in FIG. 4A, when strake 70 is rotated up out of the liquid,it carries liquid up and out of the wastewater pond. This carried liquidescapes through bleed holes 78, thereby creating additional liquidsurface area which comes into contact with air, thereby resulting in anadditional transfer of gas to the liquid. When strake 70 is rotated downinto the liquid, it carries air down into the wastewater pond. The airescapes through a plurality bleed holes 78, thereby creating additionalsubmerged air which comes into contact with liquid, resulting inadditional transfer of gas to the liquid.

Referring now to FIG. 4B, a top sectional view of two sets of pluralityof discs 60 intermeshed amongst each other are shown. Leading drive 42is connected to leading shaft 43 and one or more disc 60 (shown asleading disc assemblies 81, 83, 85, and 87) are preferably affixed toleading shaft 43. Trailing drive 44 is connected to trailing shaft 45and one or more disc 60 (shown as trailing disc assemblies 92, 94, 96,98, and 99) are preferably affixed to trailing shaft 45. Theillustration shown in FIG. 4B is not a specification or limitation onthe number of discs 60 in either array of discs or the number of shaftsor the number of drives. These variable parameters are determined by thedissolved gas requirements and other application requirements of theliquid being treated. The leading and trailing disc assemblies areplaced in parallel, with their properly spaced discs placed in anoverlapping, interlaced relation. Spacing between the discs 60 ispreferably accomplished using keyed hub 62; however, spacers (not shown)can be used. Preferably, the overlap between leading and trailing discassemblies is 45% of the diameter of disc 60; however, the amount ofoverlap between the two sets of discs may be adjusted by varying theparallel spacing of leading shaft 43 and trailing shaft 45 provided thedistance is less than the disc 70 radius.

Referring now to FIG. 5, an enlarged partial sectional view of aeratordevice 10 is shown, to facilitate explanation of the dynamics of mixingarea 100. Strakes 70 on leading disc 81 captures liquid from thewastewater pond and carries it up into the mixing area 100. Strakes 70on trailing disc 92 captures air from underneath dome 12 and carries itdown into mixing area 100, in addition to pushing liquid down intomixing area 100. Discs 81 and 92 and their two strakes 70 moving inunison together create shear force F between the upward and downwardmoving liquid within the mixing area, resulting in shear force F thatdrives air into the oxygen depleted wastewater. Shearing force F occursin oxygen rich mixing area 100 resulting in an increased transfer ofoxygen into the wastewater.

Referring now to FIG. 5, an enlarged partial sectional view of aeratordevice 10 is shown, to facilitate further explanation of additionaldynamics of liquid gas mixing area 100. Strakes 70 on the leading disc81 captures liquid from the wastewater pond and carries it up intomixing area 100. Plurality of bleed holes 78 in trailing face 75 ofstrake 70 on leading disc 81 will leak liquid into mixing area 100 asfluid eddies. Strake 70 on the trailing disc 92 captures air fromunderneath dome 12 and carries it down into mixing area 100. Pluralityof bleed holes 78 in trailing face 75 of the strakes on trailing disc 90leak flurries of air bubbles into mixing area 100. The flurry of airbubbles and fluid eddies combine in mixing area 100, thereby creating anincreased transfer of oxygen into the wastewater.

The disc assemblies can be set in motion rotating in unison, or, theindividual drive speeds can be utilized, thereby allowing foressentially infinite combinations of liquid and air, shearing forces,liquid eddies, and/or flurries of bubbles, thus allowing for optimumtransfer of oxygen into the wastewater.

It is contemplated in an alternate embodiment that aerator device 10 issuitable for utilization and adaptable without flotation device 14 foruse in a pipe, such as a discharge pipe. Furthermore, it is contemplatedin an alternate embodiment that aerator device 10 is adaptable withoutlower housing 18 for use in a pipe, such as a discharge pipe. Aeratordevice 10 is preferably mechanically affixed and positioned inside thepipe. Preferably, the flow rate of the liquid in the pipe is adjusted tomaintain the liquid level where both disc assemblies are preferablypartially submerged in a liquid medium, preferably at a depth of atleast 40% of their diameter; however, both disc assemblies can besubmerged in a liquid medium to any depth, wherein at least part of thedisc assemblies are exposed to the atmosphere under dome 12.

Referring now to FIG. 6, a standard industrial waste water or dischargepipe 50 is shown. Referring now to FIG. 7, wherein discharge pipe 50 isshown with section 50A removed from discharge pipe 50 and replaced withsealed enclosure 112. Preferably, enclosure 112 is inserted into thespace where section 50A was removed so as to define a space orcompartment 115 for containing mechanical agitation of aerator device100. Enclosure 112 preferably is welded to discharge pipe's 50 ends 152,which remained after cutting or removing section 50A from pipe 50. It iscontemplated that enclosure 112 is preferably constructed of an airtightand corrosion resistant material such as fiberglass, metal or the like.That is, enclosure 112 may be constructed of any material capable ofholding the area defined by space or compartmental enclosure 115 sealedat a selected, preferably increased barometric pressure. It isrecognized that other suitable materials could be utilized withoutdeparting from the intended scope of the present invention. Moreover,enclosure 112 may be affixed to discharge pipe's 50 ends 152 utilizingepoxy, nuts and bolts compressing a seal or sealant or other means knownto one of ordinary skill in the art. Enclosure 112 is further dividedinto upper section 113 of compartment 115, which creates a space abovewaterline 124 and lower section 114 of compartment 115, which creates aspace below waterline 124 that contains the liquid medium flowingthrough discharge pipe 50 and enclosure 112. Similar to FIG. 1, uppersection 113 of compartment 115 creates a space above waterline 124 thatcan collect foam and odor generated by aerator device 100. Foamgenerated by aerator device 100 is thus held in close proximity toaerator device 100 and must travel back beneath waterline 124 to escapeupper section 113 of compartment 115, further enhancing the transfer ofgas to the liquid. Odorous gases generated by the mechanical agitationof aerator device 100 are also trapped in upper section 113 ofcompartment 115 preventing their escape into the surrounding environmentresulting in an essentially odor free operation. In addition, uppersection 113 of compartment 115 acts as a sound barrier, trapping thenoises generated by the mechanical agitation of aerator device 100,preventing their escape into the surrounding environment, and therebyresulting in an essentially noiseless operation.

Referring now to FIG. 8 is illustrated an alternate embodiment of afully enclosed in pipe aerator device 100. Aerator device 100 is amechanical gas dissolving apparatus operating in a controlledpressurized environment of a discharge pipe 50. In pipe aerator device100 operates similar to aerator device 10 of FIGS. 1-5; however, in-linepipe aerator device 100 does not include dome 12, flotation device 14,and lower housing 18. As in FIGS. 1-5 in pipe aerator device 100includes discs 160 each having strakes 70 as shown in FIGS. 3-5operating as described in FIGS. 1-5 above functioning to transfer gas toliquid, especially for increasing the concentration of dissolve oxygenin the liquid medium of pipe 50.

Blower 116 is preferably any common industrial variable speed rotarytype blower similar to blower 16 of FIG. 1. Blower 116 can be of anystandard design with air flow and pressure ratings capable of increasingthe barometric pressure of the air in compartment 115 to preferablybetween approximately 35-40 inches of mercury or 1-3 psi, however,greater barometric pressure can be utilized depending on the gas andliquid medium being mixed. Blower 116 is preferably a single unitpositioned proximate upper section 117 of enclosure 112; however, blower116 can be in the form of a single or multiple blowers and can belocated anywhere on in-line aerator device 100 that permits air flowaccess to interior compartment 115 of enclosure 112. In addition, blower116 may be remotely positioned relative to compartment 115 of enclosure112 and pressurized air from blower 116 may be piped or tubed fromblower 116 to compartment 115 of enclosure 112. In the preferredoperation, blower 116 increases the barometric pressure in compartment115 of enclosure 112 creating an ideal environment for the transfer ofgas to the liquid in compartment 115 of enclosure 112, whereincoincidentally surface area is increased via agitation and whirling ofliquid by aerator device 100. In addition, the increase in barometricpressure under in compartment 115 of enclosure 112 assists with poppingthe foam bubbles, effectively reducing the foam generated by aeratordevice 100.

Blower 116 can preferably be used for facilitating fine adjustment ofwaterline 124 in compartment 115 of enclosure 112 by increasing ordecreasing the barometric pressure of the air in compartment 115, thusmaintaining the waterline 124 at a predetermined position relative todiscs 160. By increasing the air pressure in compartment 115 ofenclosure 112, blower 116 causes waterline 124 to lower forcing theliquid medium out of enclosure 112 and into pipe 50. In contrast, byreducing the air pressure in compartment 115 of enclosure 112 blower 116causes waterline 124 to rise allowing the liquid medium to enterenclosure 112 from pipe 50. Moreover, blower 116 with feedback fromsensor 119 allows for user-controlled or controller controlled heightadjustment of waterline 124 in compartment 115 of enclosure 112 inrelation to discs 160 optimizing dissolve gas in the liquid medium ofpipe 50.

Sensor 119 preferably represents one or more sensors, including but notlimited to sensors to detect water level, gas pressure, the amount ofdissolved gas in the liquid medium, and humidity inside compartment 115of enclosure 112 and to provide a representative signal of suchinformation for feed back to a controller, user, or directly to blower116. Various means of sensing and types of sensors to detect waterlevel, gas pressure, the amount of dissolved gas in the liquid medium,and humidity are known to one of ordinary skill in the art and arecontemplated herein.

Referring now to FIG. 9, illustrates an alternate embodiment of atethered aeration apparatus 200 of FIG. 1. Anchor device 210 ispermanently affixed to river or tidal bed 224 and extends abovewaterline 222 to provide stationary anchor support for tethered aerationapparatus 200. It is contemplated herein that anchor device 210 may beany device capable of securing tethered aeration apparatus 200 in amoving liquid medium such as river flow, tidal movements and the like,including but not limited to buoys. Swivel attachment 226 provides ananchor point for one end 227 of cable 228 to affix to anchor device 210and the other end 229 of cable 228 is affixed to eye 132 anchoringtethered aeration apparatus 200 relative to anchor device 210, thuspulling tethered aeration apparatus 200 through liquid medium showntravelling in the direction of arrows 251. As river current shift ortidal waters alter direction tethered aeration apparatus 200 preferablyshifts positions down stream from anchor device 210 continuing to scoopflowing liquid medium into open end 21, referenced as the intake 21shown in FIG. 1.

Tethered aeration apparatus 200 operates similar to aerator device 10 ofFIGS. 1-5. As in FIGS. 1-5 tethered aeration apparatus 200 includesdiscs 160 each having strakes 70 as shown in FIGS. 3-5 operating asdescribed in FIGS. 1-5 above functioning to transfer gas to liquid,especially for increasing the concentration of dissolve oxygen in theliquid medium.

It is contemplated herein that tethered aeration apparatus 200 may bemoved or tugged (tug boat) to different locations and re-anchoreddepending on river flow, tidal conditions and/or gas to liquid transferrequirements, especially to achieve dissolve oxygen levels in the liquidmedium of interest.

Recumbent generator 240 is shown in this embodiment of the tetheredaeration apparatus 200, but may be utilized in the in-pipe aeratordevice 100 as well. Preferably, liquid medium flows past leading disc181 forcing leading disc 181 to turn in the direction of liquid mediumshown travelling in the direction of arrows 251 (FIG. 9) or arrow 51(FIG. 8). Likewise, liquid medium flows past trailing disc 192 forcingtrailing disc 192 to turn in the direction of liquid medium showntravelling in the direction of arrows 251 (FIG. 9) or arrow 51 (FIG. 8).Preferably recumbent generator 240 generates power from one or bothleading disc 181 and/or trailing disc 192 rotations and utilizes theelectric power generated by recumbent generator 240 to compensate forany lag occurring in either leading disc 181 and/or trailing disc 192 bypowering drive 28 with electric power generated by recumbent generator240, thus enabling synchronized or un-synchronized rotation of discs 60.

Land based power may be supplied to tethered aeration apparatus 200along cable 228 or locally generated power may be generated by energydevice 250. Energy generation device 250 may include, but is not limitedto solar, wind, static electricity, photovoltaic, electric generatorand/or storage batteries.

Having thus described exemplary embodiments of the present invention, itshould be noted by those skilled in the art that the within disclosuresare exemplary only, and that various other alternatives, adaptations,and modifications may be made within the scope of the present invention.Accordingly, the present invention is not limited to the specificembodiments illustrated herein, but is limited only by the followingclaims.

1. An apparatus for treating liquid by exposing the liquid to gas, theapparatus comprising: a) a pipe having an enclosure positioned in-linewith said pipe, wherein a sealed space is defined in said enclosure; b)an aeration means positioned within said sealed space and partiallysubmerged in the liquid medium flowing from said pipe and saidenclosure, wherein said aeration means comprises one or more parallelshafts, at least one first disc positioned axially on one of saidshafts, at least one second disc positioned axially on another of saidshafts, wherein said second disc is interleaved relative to said firstdisc, and wherein a surface of said first disc rotates in a directionopposite a surface of said second disc relative to each other resultingin a mixing area therebetween; and c) at least one blower, said blowerdisposed in a position enabling an effect therefrom on the barometricpressure in said sealed space.
 2. The apparatus of claim 1, wherein saidfirst and said second discs drive gas into the liquid increasing thedissolved gas in the liquid.
 3. The apparatus of claim 1, furthercomprising a plurality of discs, said plurality of discs furthercomprising a leading disc and a trailing disc.
 4. The apparatus of claim1, further comprising at least one variable speed drive for rotatingsaid shafts.
 5. The apparatus of claim 1, further comprising at leastone strake carried by said first disc, each of said at least one strakedefining a channel with end caps, and at least one strake carried bysaid second disc.
 6. The apparatus of claim 5, wherein said at least onestrake is radially disposed.
 7. The apparatus of claim 5, furthercomprising a plurality of bleed holes, said bleed holes defined in atrailing face of each said strake.
 8. The apparatus of claim 1, whereinsaid blower creates a variable barometric pressure in said sealed space.9. The apparatus of claim 4, further comprising a controller, saidcontroller adapted to control said drive speed.
 10. The apparatus ofclaim 9, wherein said controller has wireless controls.
 11. Theapparatus of claim 1, further comprising at least one sensor.
 12. Theapparatus of claim 11, wherein said sensor measurement is selected fromthe group consisting of dissolved oxygen, waterline height, gaspressure, dissolved gas in the liquid medium, or humidity.
 13. Theapparatus of claim 1, wherein said first disc carries the gas into saidmixing area and said second disc carries liquid into said mixing areaproducing a shear force between the gas and the liquid increasing thedissolved gas in the liquid.
 14. The apparatus of claim 5, wherein saidstrake on said first disc carries gas down into said mixing area andsaid strake on said second disc carries liquid up into said mixing areaproducing a shear force between the gas and the liquid increasing thedissolved gas in the liquid.
 15. The apparatus of claim 8, wherein adecrease in said barometric pressure raises the waterline in said sealedspace.
 16. The apparatus of claim 8, wherein an increase in saidbarometric pressure pops air bubbles created by said aeration meanswithin said sealed space resulting in reduced foam.
 17. The apparatus ofclaim 8, wherein an increase in said barometric pressure lowers thewaterline in said sealed space.
 18. The apparatus of claim 8, wherein anincrease in said barometric pressure enhances contact between said gasand said liquid within said sealed space.
 19. The apparatus of claim 4,wherein said variable speed drives for rotating said shafts operate atdifferent speeds.
 20. The apparatus of claim 4, further comprising arecombinant generator, said generator adapted to assist at least onevariable speed drive.
 21. The apparatus of claim 4, further comprisingan energy generation device, said energy generation device adapted toprovide local power for said apparatus.